This invention relates to optical systems for use in distance measurement or range-finding devices. More particularly, this invention relates to single beam optical systems in range-finding and measurement devices.
Dual beam range-finders are commonly used to determine distances. In current applications of range-finders, the size, weight and cost of the range-finding system may typically be ignored. Conventional range-finding systems are used to determine distances for agriculture, aviation and nautical applications.
Although these dual beam systems are adequate for current uses, simultaneous reductions in all four dimensions of size, weight, complexity and cost could enhance distance measuring or range-finding systems for broader or mass market uses. Furthermore, existing dual beam systems also exhibit dead zones, which it would be desirable to eliminate.
As shown in FIG. 4, a typical dual beam range-finding system 300 includes one beam path 318 for a transmit system 310 (comprising one transmit source 312 transmitting one beam 314 through one lens 316) and another beam path 328 for a receiving system 320 (comprising a reflected beam 324 passing through a second lens 326 and being received by a receiver 322).
In the dual beam system 300 of FIG. 4, the transmit source 312 of transmit system 310 emits light that travels through the lens 316. This light becomes the collimated outbound beam 314. The outbound beam 314 hits a target (an object in space such as, for example, a building, a bar code on the building or an identification unit mounted on the building). The outbound beam is reflected from the target and returns to the receiving system 320 of the dual beam system 300 via beam path 328. As this reflected beam 324 passes through lens 326, it is refracted so that it comes to a focus at receiver 322. The angle between the outbound beam path 318 and return beam path 328 may be zero or some small angle. The area A within the angle formed between the beam paths 318 and 328 is considered a dead zone, in which no target can reflect a return beam 324 that will be caught and returned by lens 326 to receiver 322.
The techniques of optical beam combination have been used in other optical systemsxe2x80x94such as microscopes that incorporate laser based micro-machining systems. However, the application of these techniques to distance measuring or range-finding systems for the purposes of reducing the overall system size, weight, complexity and cost would be desirable.
Multiple technologies may also be integrated into a given range-finding or distance measurement system. Such integration of multiple technologies into one range-finding system would also make it desirable to render each component of the range-finding system, particularly the optical system, as compact as possible.